Manufacture of fabrics



' manufacture of. embroidery and the "tion.

Patented Dec. 19, 1944 Thomas Leigh Williams, or to E. I. du Pont de N mingto 11, Del.,

New York. N. Y., assignemours & Company, Wila corporation of Delaware Application April 10, 1942, Serial No. 438,455

' 9 Claims. (01. 2278) This invention relates to improvements in the like. to the use of polyvinyl alground or support on which lace specifically, it relates cohol film as the is formed.

The commercial manufacture of lace involves the use of a ground fabric or foundation upon which the lace is embroidered, stitched, or formed. The ground fabric or foundation used in lace-making is ordinarily of such'character that it can be removed from the composite fabric without injuring the lace. Thus, for example the common ground fabric material chosen for use in lace-making is silk which can be removed by treatment with an aqueous solution of caustic soda without damaging the material, e. g., cotton, of which the lace fabric is composed.

There have been certain disadvantages in the use of materials which have been suggested for use as ground fabrics in the manufacture of lace.

I For example, where heat is used to carbonize the ground fabric, the lace is often injured by the acid vapors produced intheheat necessary to.

carbonize. Where the ground fabric is removed by solvent action, the solvent used may damage the lace fabric itself and may in the case of certain solvents, e. g., hazard on account of inflammability or similar dangerous characteristics. Furthermore, the prior art ground fabrics are expensive and their removal takes considerable time, thereby increasing the cost of the process. Silk backings, for example, which are in common use, take from oneto three hours to dissolve in a caustic salt:-

It is, therefore, an object .of this invention to provide an improved type of foundation or support in the manufacture of lace and like fabric.

acetone, present a definite More It is a further object of the present invention to provide a foundation or support in the manufacture of lace composed of a thin film of high durabilitmwhich can be sewed without tearing and on which embroidery can be stitched and accurately produced ccording to any desired pattern.

It is a further-object to provide a foundation or support in the manufacture of lace, which canbe easily and quickly removed from the lace'with out harming the lads fabric.

Other objects of the. present invention will appear hereinafter.

The accompanying drawing cally a partial lace fabric transparent fllmsupport, support from the lace.

illustrates graphiembroldered on a prior to removal of the The objects of this invention are accomplished, in general; by the use of an adequately softened or plasticized water-soluble polyvinyl alcohol film as the foundation or support in the manufacture of lace by the embroidery method.

In the practice of the present invention, a film or sheet of water-soluble polyvinyl alcohol of suitable size, strength and thickness, is positioned on any of the known lace-making machines in the same manner as when using the ground fabrics of the lace-making processes and operations are used to form lace .on the film foundation. After the lace is stitched or embroidered onto the foundation or backing, the composite article is removed to the washing operation where the water-soluble polyvinyl alcohol foundation is dissolved from the lace with water or with an queous solution of sodium hydroxide or other suitable solution. The washing solution may be hot or cold, depending upon the particular polyvinyl alcohol used to make the film. For erample, if the polyvinyl alcohol is prepared by saponifying polyvinyl acetate esterifled) until all but"3.5% of the acetyl groups are removed, the material is soluble in cold water, while if the saponiflcation continues until all but about 5% by weight of acetyl groups are removed, hot water must he used to dissolve'it. The resulting lace exhibits no undesirable effect resulting from the use of the polyvinyl alcohol film as a foundation or from its method of removal therefrom.

A film suitable for use in present invention should ness to be self-supporting thick nor so elastic nor be of sufficient thickand should not be so tacky that the needles can not get through it far enough to complete on the back side of the the stitches of the lace I film. The water-soluble polyvinyl. alcohol mm a thickness of from about 0.0005 to 0.01 inch and should preferably be from 0.0015 to 0.003 inch in thickness.

The film, in additi which softens or plasticises prior art. The standard.

accordance with the should contain a material I the film in order to impart proper softness, flexibility and toughness.

Thus, a plasticizer such as glycerine, the alkylolamides (e. g., ethanolformamide and ethanolacetamide) disclosed in Watkins United States Patent, No, 2,250,664, or the beta-hydroxy-alkyl ammonium salts, disclosed in Watkins United States Patent No. 2,271,468, may be incorporated into the film-forming composition or otherwise incorporated into the film. The plasticizer should be present in an amount from 2% to based on the weight of the dry (solvent-free and water-free) polyvinyl alcohol in the film, and preferably the plasticizer should be present within the range of 12% to 18% based on the weight of the dry polyvinyl alcohol Unplasticized film, however, may be used successfully in an atmosphere of high relative humidity, since the film absorbs moisture from the highly humid air and is plasticized by the absorbed moisture. Where water alone is used as the plasticizer for the film, the water content should be within the range of 6% to 25%, based on the weight of the dry polyvinyl alcohol in the film.

Useful results are obtained with polyvinyl alcohol film which contains little or no orientation of the molecules. For the best results, however, it is preferred that the molecules in the film be oriented, which orientation may be produced by stretching the film. Advantageous results are obtained with the molecules of the film oriented either in the longitudinal or transverse direction, or both. The orientation causes an. increase in tenacity in the direction of stretch. For the optimum results, however, it is preferred that the film be oriented at least in the transverse direction since most of the tension or strain on the film is in that direction. For example, a film to be used on a machine which handles a ground fabric 31 /2 or feet in length and 4 feet in width should be stretched in a known manner in the width direction in order to orient the film in the width or transverse direction since the strain imposed during the manufacture of the lace is greater in the transverse direction.

It is to be noted that where the film is oriented,- ncfurther substantial stretch in the direction of orientation takes place after the film is mounted on the embroidery frame because of absorption of moisture from the air, since the capacity of polyvinyl alcohol to stretch under tension, when its water content is increased, is much lower with oriented film than with unoriented film, and becomes less as the degree of orientation increases.

Polyvinyl alcohol is generally produced by the sapom'fication of polyvinyl esters, e. g., polyvinyl acetate. The retention, after saponification, of 35% or less of the acetyl radicals contained in completely acetylated polyvinyl acetate, is suflicient to produce a' water-soluble product. Similarly, a completely saponiiled polyvinyl acetate can be reacted with butyraldehyde to the extent of up to 9% of the hydroxyl groups of the polyvinyl alcohol with the formation of the partial butyral, without destroying the water solubility. Other aldehydes may be used in place of butyraldehyde in producing polyvinyl aceta'ls provided that the amount of aldehyde incorporated into the polyvinyl product is not in excess of that which will produce a water-soluble product. If acetaldehyde is used in place of butyraldehyde, one can react up to of the hydroxyls of the polyvinyl alcohol (completely saponifled polyvinyl acetate) with the production of a watersoluble ac'etal. Such water-soluble compounds present in the film.,

are all suitable for use in accordance with the present invention. -However, polyvinyl alcohol which has been produced by the saponificatinn of completely esterified polyvinyl acetate to remove at least 95% of the acetyl radicals has better physical properties and can be handled more readily than less completely hydrolyzed polyvinyl acetate; for example, the film is less tacky and since it resists the weakening effect of moisture absorbed from the air, facilitates passage of the needle therethrough instead of flexing away from Y the needle as in the case of the less completely saponified film. This type of polyvinyl alcohol is, therefore, a preferred species of the present invention.

In referring, throughout the specification and claims, to per cent of acyl radicals, groups or content in the polyvinyl compounds, it is intended to refer to the per cent of acyl ascompared with the polyvinyl ester possessing 100% of theacyl groups which can be included in the molecule. Thus 100% acetyl content signifies completely esterified polyvinyl acetate.

The term "polyvinyl alcohol, as used throughout'the specification and claims, unless otherwise limited, is intended to include only water-soluble polyvinyl hydroxyl compounds containing substituent non-hydroxyl groups such as acyl or aldehyde not in excess of 35% of the maximum possible content of such substituent groups.

In order for the film to have sufficient strength and durability to withstand the lace-making operation, the polyvinyl alcohol from which the film is made should have a molecular weight of between 10,000 and 22,000, and preferably'the molecular weight should be between 15,000 and 19,000.

The following examples will specifically illustrate the invention. Parts are given by weight throughout the application unless otherwise specified.

Example I Polyvinyl alcohol film, containing 15% by weight of glycerine (based on the water-free weight of the polyvinyl alcoholof the film) and having a thickness of 0.002 inch,-is prepared by wet casting from polyvinyl alcohol produced by saponifying polyvinyl acetate down to 5% acetyl content, the resulting saponified compound having a molecular weight of 18,000. A piece of this film 31 /2 feet in length, 4 feet in width, is mounted on a standard lace-making machine in the usual manner and drawn tight. Using a standard operation, lace is formed on this support, using a 40 count cotton yarn. When the operation is complete; the film containing the lace thereon is removed from the machine and treated with water at C. for forty minutes. At the end of this time, the polyvinyl alcohol support has been completely dissolved away leaving the lace.

Example II A sheet of polyvinyl alcohol having a. thickness of 0.0015 inch and containing 15% ethanolformamide (based on the water-free weight of the polyvinyl alcohol in the film) is prepared by wet from polyvinyl alcohol which is produced by saponifying polyvinyl acetate down to 3% of acetyl content, vinyl alcohol having a molecular weight of 15,000. This sheet is oriented in the conventional way by stretching in the transverse direction. A sheet of this material 31 /2 feet long and 4-feet wide is mounted on a standard lace-making machine and drawn tight. Using a standard prosaid polyand removing the film.

' is easily and quickly making of lace fabric.

motes the use of silk and other moved and treated with 6% caustic soda solution at 85 C. for 15 minutes. The polyvinyl alcohol support is completely removed inthis period. A final washing with hot water at 85 C. removes A lace of excellent quality is obtained.

The films or sheets used in the present invention may be sized or not as desired. One size which has been used successfully is composed of polyvinyl butyral resins. The invention, however, is not limited to any particular size and is further not limited to the use of a size. I

By the use of the present invention, lace may be made .from yarns of any material not deleteriously afiected by the liquid used in dissolving These yams may range in size from 20 counts to 120 counts, which are, the more common ones used in the lace art.

The invention'has been described in terms of I a process for the manufacture of lace. However,

it is evident that the invention is applicable to all similar processes involving the use of a support, which is subsequently to be removed.- In the specific process of manufacturing lace by embroidering, any f the standard lace-making processes and apparatus may be" used.

The lace support or invention is easily, produced by the manufacture of a film, thereby eliminating all of the spinning and weaving operations heretofore used to produce ground fabrics. .The polyvinyl alcohol sheet many different types of yarn may be used in the asthe, support in commercial lace-making, eliminated silk as the lace fabric material, since any attempt to remove the silk backing would destroy the lace. The present invention, therefore, pro-' fibers such as wool, cellulose acetate and other natural and synthetic fibers in the commercial manufacture of lace by embroidery processes. V

The film of the present invention has a further pieces of film may be put together to form one large film to fit the lace-making machines by the simple procedure of heat-sealing" the edges of the The pieces of film may be sewed together if desired. However, this latter procedure requires an extended dissolving period foundation of the present I use of'the present invention,

Heretoi'ore, the use of silk,

- the 'caustic remaining from the previous washing.

, 3 alcohol thread, this less marked than where some other thread, such as silk thread,'is used.

It is well-known that polyvinyl alcohol is an cellent size or finish for yarns and fabrics. A lace containing a size maybe obtained bythe process of the present invention film of the present invention fulfills is that the foundation must be able to withstand sewing in which hundreds'and even thousands of stitches are made per square inch. of the present invention has a very high resistance to tearing and permits the many stitches to be made in it as required in this art.

Since it is obvious that many changes and modifications can be made in the details described above without departing from the nature and spirit 011 the invention,- it is to be understood that the invention is not to be limited to said details except as set forth in the appended claims.

I claim:

1. The method 01' maklngJace fabric and the like which comprises stitching the fabric on a removed from the lace by the use of water or caustic solution and does not .the

which contains a 2. The method plasticizing medium. of claim 1 characterized in that the polyvinyl alcohol molecules are transversely oriented.

3. The method of claim 1 characterized in that polyvinyl alcohol contains 5% or less of acetyl groups.

- 4. The method'of making lace fabric and the like which comprises stitching the fabric on a plasticizing medium and removing the film by dissolvin in an aqueous niedium.

5. The method of, claim 4 characterized in that 'the polyvinyl alcohol molecules are transversely oriented.

f6. The method of claim 4 characterized in that the polyvinyl alcohol contains 5% or less of acetyl groups.

a. The article of claim '1 characterized in that the polyvinyl alcohol contains 5% or less oi acetyl groups. v

THOMAS LllliGH- WILLIAMS;

disadvantage becomes much The lace foundation 

